Cross-cultural studies of age and menopause related skeletal changes are absent and detailed research addressing this issue will contribute new insight into the study of menopause, aging, and osteoporosis. The aim of this proposed cross-cultural study upon is to provide comparative data on the patterns of age-related skeletal and hormonal status in women in a culture which is unlike Western industrialized societies. The culture selected for the study is rural Mayan women in southeastern Yucatan, Mexico. Data from preliminary research indicate that, unlike women in industrialized Western societies, most Mayan women marry early in their teens. Since they do not use contraceptive methods, many pregnancies occur at two-year intervals. The average number of pregnancies for these women is seven. Breast-feeding continues for one and a half to two years, with lengthy lactation amenorrhea. Moreover, these women experience relatively early onset of menopause with the average at 42 years. Menopause occurs before the age of 40 in almost half of the women sampled, and none reported experiencing typical menopausal symptoms such as hot flashes. Furthermore, preliminary data indicates that Mayan women have a high calcium and low protein diet, maintain a relatively high level of physical activity, are obese, and do not smoke or drink alcohol. The selected culture would provide a unique and relatively isolated control for several risk factors which are assumed to be associated with postmenopausal osteoporosis, therefore, allowing us to identify the specific role of estrogen deprivation on skeletal health. The methods of data collection will include: a survey of prevalence of fractures in the population from clinical and hospital records, physical examination, blood analysis, bone density studies, and complete reproductive history of 100 rural and 100 urban Mayan women, as well as dietary calcium analysis in local foods. The findings will provide cross-sectional data on age- related skeletal and hormonal status of women in a culture which is unlike Western industrialized societies.